central meridian An imaginary line bisecting the apparent disk of a planet or the Sun and joining the poles of rotation. The passage of a surface feature across the central meridian, due to the axial rotation of a planet, is known as a central meridian transit. The timing of central meridian transits is an important means of determining the planetographic longitudes of planetary surface features. Related category • CELESTIAL MECHANICS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |